Migraine and the Autonomic Nervous System

This chapter focuses on migraine and the autonomic nervous system, examining autonomic symptoms in the course of the migraine attack. Migraine is a syndrome of recurrent headaches manifesting in attacks lasting 4 to 72 hours, with typical unilateral localization, pulsating quality, moderate to severe intensity of the pain, aggravation by or avoidance of routine physical activities, and association with nausea and/or vomiting and photo- and phono-phobia. The cerebral vessels and the meninges represent the main pain-sensitive structures of the head. Sensory fibers to cranial structures derive from the trigeminal nerve and ganglion. Neurologic signs of enhanced parasympathetic outflow to the head are found during migraine attacks in 73% of subjects, often bilaterally. The brain contains no pain fibers and the only way it may signal pain is through the trigeminovascular system. Migraine is conventionally portrayed as a pain disorder, even though pain represents just the tip of the migraine iceberg, may even be absent and it is preceded by prodromes separated from the aura.